<div class="swiper-container">
  <div class="swiper-wrapper">
    <div class="swiper-slide" *ngFor="let item of imgArr">
      <img src="{{item.rotation_img}}">
    </div>
  </div>
  <div class="swiper-pagination"></div><!--分页器。如果放置在swiper-container外面，需要自定义样式。-->
</div>
